Electronic enclosure including a flame arrestor having a mechanical check valve

ABSTRACT

An electronic enclosure includes a housing having a plurality of walls that define an interior portion. A flame arrestor is mounted to one of the plurality of walls of the housing. The flame arrestor includes a mechanical check valve. The mechanical check valve is configured and disposed to allow a fluid to exit the interior portion of the housing and prevent fluid from entering the interior portion of the housing.

BACKGROUND OF THE INVENTION

Exemplary embodiments pertain to the art of electronic enclosures and,more particularly, to an electronic enclosure having a flame arrestorincluding a mechanical check valve.

Certain electronic enclosures, particularly those employed inenvironments containing flammable gases or liquids, are required byvarious standards setting institutes to include an explosion proofdesignation. The explosion proof designation denotes that the enclosureis designed to prevent internal combustions from exiting and ignitingexternal flammable substances. In some cases, the enclosure includes aflame arrestor that prevents a flame front initiating within theenclosure from exiting to the surroundings.

Flame arrestors function by forcing a flame front through channels toonarrow to permit continuation of a flame. The particular form of thechannels can vary. For example, flame arrestors may include regularchannels, such as those defined by a wire mesh or openings formed in asheet metal plate, or irregular channels such as those provided with arandomly packed material. The particular size of the channels can varydepending upon the flammability of any associated fuel.

BRIEF DESCRIPTION OF THE INVENTION

Disclosed is an electronic enclosure that includes a housing having aplurality of walls that define an interior portion. A flame arrestor ismounted at one of the plurality of walls of the housing. The flamearrestor includes a mechanical check valve. The mechanical check valveis configured and disposed to allow a fluid to exit the interior portionof the housing and prevent fluid from entering the interior portion ofthe housing.

Also disclosed is a motor drive system including a fan housing unithaving a housing member provides with an interior zone. A motor driveunit is connected to the fan housing unit. The motor drive unit includesa housing having an interior portion. The housing includes at least oneflame arrestor having a mechanical check valve moveable between a firstposition that fluidly isolates the interior portion and a secondposition that allows passage of fluid from the interior portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 is a lower left perspective view of a motor drive system inaccordance with an exemplary embodiment;

FIG. 2 is a partially cut way view of the motor drive system of FIG. 1illustrating flame arrestors including mechanical check valves explodedfrom a motor drive unit;

FIG. 3 depicts the mechanical check valves of FIG. 2 in a closedconfiguration;

FIG. 4 depicts the mechanical check valves of FIG. 2 in an openconfiguration;

FIG. 5 depicts mechanical check valves in accordance with another aspectof the exemplary embodiment in a closed configuration; and

FIG. 6 depicts the mechanical check valves of FIG. 5 in an openconfiguration.

DETAILED DESCRIPTION OF THE INVENTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

A motor drive system 1 includes an electronic enclosure or motor driveunit 2 in accordance with an exemplary embodiment illustrated generallyat 2 in FIG. 1. Motor drive unit 2 is mounted to a fan housing unit 3having a motor housing unit 4. Motor drive unit 2 includes a housing 8having a first wall 10, a second wall 11, a third wall 12, a fourth wall13 and a bottom wall 15 that collectively define an interior portion 17that houses a motor drive control 20. Motor drive control 20 isconfigured and disposed to control a fan motor 25 (FIG. 3) arrangedwithin motor housing unit 4. Fan motor 25 drives a fan 30 that isdisposed within an interior zone 33 of fan housing unit 3. In theexemplary embodiment shown, fan 30 takes the form of an axial fan. Infurther accordance with the exemplary embodiment, motor drive unit 2 isprovided with a plurality of flame arrestors 40-43. Flame arrestors40-43 allow a flame front to pass from motor drive unit 2 into interiorzone 33. In addition, flame arrestors 40-43 can also prevent moisturefrom entering motor drive unit 2 from interior zone 33 of fan housingunit 3.

Reference will now be made to FIGS. 2-4 in describing flame arrestors40-43. As each flame arrestor 40-43 is similarly formed, a detaileddescription will follow with reference to flame arrestor 40 with anunderstanding that the remaining flame arrestors include correspondingstructure. Flame arrestor 40 includes a blocking tube 60 having a firstend 62 that extends to a second end 63 through an intermediate portion65. First end 62 includes a flange 70 that is designed to cooperate withbottom wall 15 to position blocking tube 60 within interior zone 33.Second end 63 includes an angled surface 74 that minimizes any ingressof moisture from interior zone 33 to blocking tube 60. In order toprevent any moisture that may enter blocking tube 60 from entering motordrive unit 2, flame arrestor 40 includes a mechanical check valve 80positioned within blocking tube 60.

In accordance with one aspect of the exemplary embodiment, mechanicalcheck valve 80 takes the form of a duckbill valve 84 that is insertedinto blocking tube 60. Duckbill valve 84 includes a first end section 87that extends to a second end section 88. First end section 87 defines aninlet section 90 and includes a flange section 92. Flange section 92 isconfigured to locate duckbill valve 84 within blocking tube 60. That is,flange section 92 mates with flange 70 to position duckbill valve 84within blocking tube 60. Second end section 88 of duckbill valve 84defines an outlet section 96 that includes a valve member 100. Inaccordance with the exemplary embodiment, valve member 100 is formedfrom a resilient material that is designed to deflect when subjected toa predetermined pressure. More specifically, duckbill valve 84 isnormally in a closed configuration, such as shown in FIG. 3. In theclosed configuration, any moisture that may exist within motor housingunit 4 is prevented from entering motor drive unit 2. However, in theevent that a pressure build up occurs within motor drive unit 2 from,for example, a combustion event, valve member 100 deflects to the openconfiguration as shown in FIG. 4. In the open configuration, duckbillvalve 87 allows any pressure build up within motor drive unit 2 to passinto interior zone 33. At the same time, duckbill valve 84 allows anyflame front to pass into interior zone 33.

Reference will now follow to FIGS. 5 and 6, wherein like referencenumbers represent corresponding parts in the respective views, indescribing a mechanical check valve 120 in accordance with anotheraspect of the exemplary embodiment. Mechanical check valve 120 takes theform of a spring valve 122 including a first end section 129 thatextends to a second end section 130. First end section 129 defines aninlet section 134 and includes a flange section 136. In a manner similarto that described above, flange section 136 locates spring valve 122 inblocking tube 60. Second end section 130 defines an outlet section 140having a valve member 144.

In a manner also similar to that described above, spring valve 122 isnormally in a closed configuration, such as shown in FIG. 5. In theclosed configuration, any moisture that may exist within interior zone33 is prevented from entering motor drive unit 2. However, in the eventthat a pressure build up occurs within motor drive unit 2 resultingfrom, for example, a combustion event, valve member 144 opens, as shownin FIG. 6, to allow pressure to escape into motor housing unit 4. Thepressure at which valve member 144 will open is determined by a spring150 that extends between first and second end sections 129 and 130.Spring 150 biases valve member 144 into the closed configuration.However, if pressure build up within motor drive unit 2 is sufficient toovercome the biased force of spring 150, valve member 144 will shift toexpose outlet section 140 to inlet section 134 to release the pressureinto fan housing unit 4. At the same time, mechanical valve 120 allowsany flame front that may develop in motor drive unit 2 to pass intointerior zone 33.

At this point it should be understood that the exemplary embodimentsprovide an electronic enclosure including a device for preventingmoisture from passing from an interior zone into the housing whileallowing for pressure relief and flame diversion. More specifically, amotor fan installation may require a motor drive unit capable ofexplosive containment with pressure relief and flame direction controlwhen located in an explosive environment. Moreover, the sameinstallation may also require that the fan be subjected to a highmoisture environment. The explosion proof housing includes a flamearrestor(s) that provides pressure relief and flame control. However,conventional flame arresters allow moisture to pass into the motor driveunit housing. The present exemplary embodiments not only provide thepressure relief and flame control but also provide a barrier tomoisture. In this manner, the electronic enclosure can be more readilyemployed in moist environments such as condensers, evaporators and thelike.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims.

What is claimed is:
 1. An electronic enclosure comprising: a housingincluding a plurality of walls that define an interior portion; and aflame arrestor mounted at one of the plurality of walls of the housing,the flame arrestor including a mechanical check valve, the mechanicalcheck valve being configured and disposed to allow a fluid to exit theinterior portion of the housing and prevent fluid from entering theinterior portion of the housing.
 2. The electronic enclosure of claim 1,wherein the mechanical check valve includes a valve member that ismoveable between a first position that fluidly isolates the interiorportion of the housing and a second position that fluidly opens theinterior portion of the housing.
 3. The electronic enclosure of claim 1,wherein the mechanical check valve comprises a duckbill valve.
 4. Theelectronic enclosure of claim 3, wherein the duckbill valve includes aresilient valve member.
 5. The electronic enclosure of claim 1, whereinthe mechanical check valve comprises a spring valve.
 6. The electronicenclosure according to claim 1, wherein the flame arrestor includes ablocking tube including a first end exposed in the interior portion ofthe housing and a second end positioned outside the housing, the secondend including an angled surface.
 7. The electronic enclosure accordingto claim 6, wherein the mechanical check valve is positioned within theblocking tube.
 8. The electronic enclosure of claim 6, furthercomprising: another housing having an interior zone, the interiorportion of the housing being connected to the interior zone of theanother housing through the blocking tube.
 9. The electronic enclosureof claim 8, further comprising: a motor drive control arranged withinthe interior portion of the housing.
 10. The electronic enclosure ofclaim 9, further comprising: a fan motor arranged within the interiorzone of the another housing.
 11. A motor drive system comprising: a fanhousing unit including a motor housing unit having an interior zone; anda motor drive unit connected to the fan housing unit, the motor driveunit including a housing having an interior portion, the housingincluding a flame arrestor having a mechanical check valve moveablebetween a first position that fluidly isolates the interior portion anda second position that allows passage of fluid from the interiorportion.
 12. The motor drive system of claim 11, wherein the mechanicalcheck valve includes a valve member that is moveable between the firstposition and the second position.
 13. The motor drive system of claim11, wherein the mechanical check valve comprises a duckbill valve. 14.The motor drive system of claim 13, wherein the duckbill valve includesa resilient valve member.
 15. The motor drive system of claim 11,wherein the mechanical check valve comprises a spring valve.
 16. Themotor drive system of claim 11, wherein the fan housing unit comprisesan electric motor arranged within the motor housing unit.
 17. The motordrive system of claim 11, further comprising: a motor drive controlarranged within the interior portion of the motor drive unit.
 18. Themotor drive system of claim 11, wherein the flame arrestor includes ablocking tube having a first end that is exposed in the interior portionand a second end exposed in the interior zone, the second end includingan angled surface.
 19. The motor drive system of claim 18, wherein themechanical check valve is positioned within the blocking tube.
 20. Themotor drive system of claim 19, wherein the mechanical check valveincludes a flange section that locates the mechanical check valve withinthe blocking tube.